QSS: "border: 1px dashed" property produces wrong border type

#include <QApplication>
#include <QMainWindow>
#include <QPushButton>

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);

    QMainWindow window;
    auto button = new QPushButton(&window);
    button->setStyleSheet("border: 1px dashed black;");   // Will produce DOTTED border instead.
    //button->setStyleSheet("border: 2px dashed black;"); // OK - dashed border, but I need 1px width.
    window.show();

    return app.exec();
}